This invention relates to electric lamps, and more particularly, to high intensity tungsten halogen incandescent lamps having an improved mounting assembly and finding applications in studio lighting and projection lamps.
In such high intensity lamps a planar multi-filament is commonly lodged within the central region of the lamp by a relatively complex mounting assembly. In some cases, the planar multi-filament is connected to the mounting assembly by a plurality of coil support members lodged into and extending out of support bridge members of the mounting assembly. These mounting assemblies commonly have one such coil support member having a length exceeding those of the other members and which member extends into a exhaust channel of the tungsten halogen lamp formed during the exhaust process of the lamp.
Although the longer support member advantageously provides for confinement of the planar filament to the central region of the lamp, it presents certain problems during the manufacturing process of these lamps. One such problem occurs during the flushing process typically utilizing an inert gas to protect the mount structure against deleterious thermal and chemical reactions and wherein a flush tube is inserted into the exhaust channel of the lamp tube having within its confines the longer support member. During this flushing process it is typically necessary to insert the flush tube into and through the exhaust channel of the lamp so that the flush tube is placed into the bulb chamber to allow the inert gas to provide protection for the mount structure and foil seal member of the lamp. If this protection is not provided the lamp part will be damaged during the heating involved with the subsequent pinched sealing process of the lamp. The longer support member positioned in the confines of the exhaust chamber hinders the desired accomplishments of the flushing process. Further, during the subsequent filling process similar difficulties ensue. It is desired that a mounting assembly for a planar filament be provided for a high intensity incandescent lamp not having the limitations created by the longer coil support member of the mounting assembly.
Accordingly it is an object of the present invention to provide an improved mounting structure that centrally locates and maintains the planar multi-filament within the tungsten halogen lamp without the need of any excessive coil support member.